Useful way to get knobs etc made?

[Yorkie]

I've put this under 'websites' as I'm giving a link to a site, but really, the topic is about the potential for getting irreplaceable knobs made by 3-D printing. 

Beyond my wit, because you need to send a 3-D file of whatever it is you want made (in any one of 31 different colours). They then give you an instant quote. So say for example you had one knob but 3 missing off a particular radio, no doubt they could make replacement, but what they'd charge and how they'd turn out, I've on idea. It could well be prohibitive unless the radio is valuable, rather than more 'run of the mill'. Also, there's be the complication of any etch in lettering such as 'tuning' 'volume' 'tone' which knobs often, which  is then picked out in white paint. Of course, they'll be plastic - not Bakelite, so may not be a good match even if the sizes are precise.

I've seen parts in exhibitions made on 3-D printers, but after the initial hype, ('are they real or is it an April Fool spoof'?),  apart from dedicated enthusiasts, 3-D printing doesn't yet seem to have became what one might term  'mainstream'. Maybe the time will come when we could walk into a shop and say "can you knock me three of these please - I'll go for a coffee and come back in half an hour". Or maybe not?  

  http://uk-3d.com/

I think I'll still have to resort to rummaging through the boxes of knobs at the NVCF/Golborne for any elusive ones!

[tiv48]

I have thought about this not Shure about one offs but how about some thing like a dac 90a wave change knob ?
when ever they come up on ebay there are always lots of bids and sell for good money.
like you I would have no idea about creating the type of file needed.
it would be great to send a part and say make me 20 of these please and be charged about £1 each
Rob T

[Refugee]

It looks like the parts will have a very mat finish at 0.08mm per layer.
For shiny knobs it would mean lots of polishing once the part comes to you.

[Alan Douglas]

And what material? Bakelite is none too strong for (say) wavechange knobs that take a lot of torque.

[Radio Fixer]

Making plastic knobs by moulding can be done well by experts.  Here are pictures of a knob, one of a set of 3 for an Ekco AC97 made for me by a Dutch guy called Wim and a friend of Ben Dijkeman.  When I got them they were a perfect match to the one good 'chicken' waveband knob that I had.  But in 12 months they changed colour drastically. so good old Bakelite still wins for colour stability.

   
   

I asked some of the big moulding material companies about this and the reply was "it happens and there is nothing that can be done about it".

No reason to believe that anything from a 3D machine will be any better.

Gary

[Yorkie]

For anyone who doesn't know, the 'AC97' is the famous 'Robot' or 'Cyclops' Ekco, known as such due to the layout of the three front  knobs, the speaker, and the magic eye. Inwardly it has a striking resemblance to the AC77 that I'm sloooowly restoring, both having similar circuitry and a separate power supply and receiver chassis. Gary's superb AC97 restoration featured in a very well illustrated article in the BVWS Bulletin in Autumn 2008, which has helped me greatly with the AC77 - a rather uninspiring set, visually, and my first (and probably the last for me!) total strip-down and rebuild. Ben Djikman supplies quite a range of knobs, dials etc, including complete sets for certain Ekco models, but usually they're black, so fading of colours isn't an issue. The ones shown by Gary when new, in the article were then an exact match in colour. Presumably it's UV that's changed the colour?  At least the 'chicken head' know is on the side of the set rather than alongside the other knobs.

Ben was able to supply a new dial for my AC77 - excellent quality screen printed, but with continental rather than English station spellings. He did kindly say that if I could get an order together for say ten dials, he'd get a batch made with English spellings, but unlike say the A22, the AC77 is not sought after, and not particularly common as far as I can see, so ten dials is out of the question. (I guess that they must be more commonplace on the continent or he wouldn't have made any AC77 dials).  

I got as far as the pics in post 52 in this thread, and since then other diversions have occupied my time. Must try to get on with it!

http://golbornevintageradio.co.uk/forum/...p?tid=3709&page=6&highlight=AC77

Ben Djikman's website is well worth a browse:

http://www.bendijkman.nl/index.php?option=com_sobi2&catid=7&Itemid=53&lang=en

As to the 3-D printing, I assume that the material is some sort of thermoplastic. Quite how it would stand up to be drilled, tapped etc, I've no idea. Don't know if when the part has been made, it feels hard,  as Bakelite is, or 'plasticky'. My understanding of Bakelite is that it isn't simply moulded, but put under extreme pressure at high temperature - a totally different material and process.  The moulds/dies must have been eye-wateringly expensive, but for radio cabinets, cheaper than wooden ones, as was reflected in the lower price of Bakelite cabinets when wood was offered as an alternative.  I recall as a child, that Bakelite was seen as inferior to wood. No-on realised that in years to come, wooden cabinets would de-laminate and become attractive to woodworm infestation when stored in damp conditions.

Rambled Yorkie, drifting right off topic again.

[Nick]

3D printing is just a process - the material that is used is up to the manufacturer - cheap systems use a thermoplastic that is easy to lay down.

Systems that lay down successive layers are called "additive" systems; systems that remove material from a block (by milling etc.) are called "subtractive".

More exotic printers will even print in metals using lasers to sinter the material ("direct metal sintering") - really stunning stuff can be made this way., e.g.

[Radio Fixer]

Yes! it must be UV David as the back is unchanged.  I now keep a cloth over the radio and one day may spray paint the knobs although modern paints are not UV stable either.  I repaired a broken Bakelite clock with body filler and sprayed in the whole section.  At the time it was so perfect in colour and texture, I spent time flatting it to be the same as the rest,  that only close inspection gave the game away.  Now some years on the cream paint has turned virtually white.

There is another problem with spray painting the knobs in that one has gold in filled lettering that isn't very deep and so may be hard to fill after a paint layer.

I missed out on buying a set of original knobs which went for about £100 and to me it would have been worth it.

Thanks for saying the restoration was superb, it didn't come up bad if I say so myself.  On its own, on say the dining room sideboard it is a striking looking design.  Amongst lots of other sets, on a shelf it doesn't stand out but that's true of almost all radios.

   
   

Oh! and the sintered metal object is superb Nick.

Gary

[Mark Hennessy]

Wow

That's an amazing restoration - congratulations!!!

[Radio Fixer]

Now you have done it Mark and I will have to show off a little.  Thanks for the Wow though and appreciating the work that went into it.

   
   

I was even lucky to get a good, correct clover leaf eye valve for it!  They are really rare and I didn't pay a fortune from Phil Taylor.

Gary